000
acus01 kwns 230103
swody1
Storm Prediction Center ac 230100
Day 1 convective outlook
National Weather Service Storm Prediction Center Norman OK
0800 PM CDT Wednesday may 22 2013
Valid 230100z - 231200z
..there is a slight risk of severe thunderstorms from the middle Atlantic into a
portion of the northestern states...
..mid Atlantic through the northestern states...
Isolated storms with at least marginal supercell structures are
moving eastward through north central New York. Additional storms developing over Lake
Ontario will eventually move into northern New York. Vertical shear in this
region is a bit stronger than farther south with 30-40 knots effective
shear...and the low level jet is forecast to strengthen during the evening.
Threat for isolated large hail and damaging wind will persist
through at least middle evening. Also an isolated tornado cannot be
ruled out next hour or two.
Farther south a broken line of multicell storms extends from eastern PA
southward through western Virginia and western NC. This activity may continue to pose a
threat for isolated damaging wind and large hail through middle
evening...but a gradual decrease is expected to begin by 02z as the
boundary layer begins to cool.
..OH valley...
Widely scattered mostly multicell storms persist across the Ohio
Valley southward into the Tennessee Valley within modest broad cyclonic flow
regime. A convective outflow boundary was also observed from southeastern Kentucky
through western WV...moving westward. Some of the storms may briefly attain
severe levels next couple hours as they interact and merge with the
preexisting outflow boundaries. Overall coverage of any severe
reports in this region is expected to remain sparse and the activity
will undergo a gradual decrease as instability diminishes with onset
of nocturnal cooling.
.Dial.. 05/23/2013
Mesoscale Discussion
000
acus11 kwns 230022
sels mesoscale discussion
Storm Prediction Center mesoscale discussion 230021
nhz000-vtz000-maz000-ctz000-nyz000-paz000-230115-
Mesoscale discussion 0775
National Weather Service Storm Prediction Center Norman OK
0721 PM CDT Wednesday may 22 2013
Areas affected...WV...se Ohio...western PA
Concerning...Severe Thunderstorm Watch 211...
Valid 230021z - 230115z
The severe weather threat for Severe Thunderstorm Watch 211
continues.
Summary...an isolated severe threat will likely continue across ww
211 for the next few hours. The strongest cells could have a
marginal threat for wind damage and hail. Due to the marginal nature
of the threat...ww issuance is not expected beyond the 02z watch
expiration.
Discussion...latest surface analysis shows a surface low north of Lake Erie
with south to southwest flow located across eastern Ohio and western PA. Southward
across WV...an outflow boundary appears to be moving westward toward the
Ohio River where new cells have initiated in the last hour. This
convection could expand in coverage as large-scale ascent increases
early this evening due to a disturbance moving eastward through the Ohio
Valley evident on water vapor imagery. The storms should move northeastward
into eastern Ohio where objective analysis currently shows MLCAPE values
of 750 to 1000 j/kg and 30-35 knots of 0-6 km shear. This along with
0-3 km lapse rates around 7.5 c/km could support an isolated wind
damage threat. The threat should remain marginal due to weakening
instability and ww 211 will be allowed to expire on schedule.
.Broyles/Thompson.. 05/23/2013
..please see www.Spc.NOAA.Gov for graphic product...
Attention...WFO...gyx...box...btv...okx...aly...bgm...buf...ctp...
Latitude...Lon 45027129 41417320 41407665 45027498 45027129
